Endangered Status The Bonytail Chub is on the U.S. Endangered Species List. It is classified as endangered throughout its range in Arizona, California, Colorado, Nevada, and Utah. This fish lives in large, fast-flowing waterways of the Colorado River system, and the large-scale damming of the river has diminished available habitat. Water-management practices such as damming and channeling not only change the speed, location, and volume of flow, they change the temperature and the clarity of the water and block migration routes. Other threats to the Bonytail Chub have been the introduction of non-native fish that compete for food and habitat, and may prey on it or hybridize with it.